Communication apparatuses, such as cellular phones, modem devices for wireless wide area networks, or communication devices for machine to machine communication using a cellular network, are nowadays arranged to be able to communicate on a wide range of frequency bands. At start-up, the apparatus scans available frequency bands for finding a base station to establish contact with. Due to the increasing number of different frequency bands available, of which at least a few can be used at a specific location while other can be used at another location depending on local regulations for frequency allocation, the scanning procedure can take relatively long time. Scanning is further complicated if there is any interference present in the frequency bands. WO 2005/099174 discloses a frequency selection method for a wireless system where other systems might interfere within the used frequency band. Frequencies having a predetermined level of interference are avoided, and channel search thus avoids disturbed channels, whereby the search can be faster.
In addition to this, other communication technologies, e.g. non-cellular systems such as Bluetooth wireless technology, Wireless Local Area Network (WLAN) technologies, or any short-range radio technology, present at adjacent frequency bands can introduce interference that may disturb the scanning for establishing cellular communication, especially for frequencies of the scanned frequency bands that are in vicinity of such adjacent frequency bands, i.e. a noise floor at frequencies in vicinity of frequencies where such other communication technologies are used can be considerably raised. This may further increase time for establishing cellular communication, and also increase the power consumption for the scanning as the scanning procedure becomes more complex to be able to deal with the interference.
It is therefore a desire to increase efficiency of establishing cellular communication at start-up of a cellular communication apparatus.